=== Quote boolean-like string (scalar)
# Strings that could be confused with booleans should be quoted
--- perl
[ 'true' ]

--- yaml
\--- 'true'

=== Quote boolean-like string (list)
--- perl
[ [ qw{ null true false } ] ]

--- yaml
\---
- 'null'
- 'true'
- 'false'

=== Quote scalars ending in colon
--- perl
[ [ 'A:' ] ]

--- yaml
\---
- 'A:'

